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/*
 * Project: S.Ha.R.K.
 *
 * Coordinators:
 *   Giorgio Buttazzo    <giorgio@sssup.it>
 *   Paolo Gai           <pj@gandalf.sssup.it>
 *
 * Authors     :
 *   Paolo Gai           <pj@gandalf.sssup.it>
 *   Massimiliano Giorgi <massy@gandalf.sssup.it>
 *   Luca Abeni          <luca@gandalf.sssup.it>
 *   (see the web pages for full authors list)
 *
 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
 *
 * http://www.sssup.it
 * http://retis.sssup.it
 * http://shark.sssup.it
 */

/**
 ------------
 CVS :        $Id: cash.c,v 1.1.1.1 2002-09-02 09:37:41 pj Exp $

 File:        $File$
 Revision:    $Revision: 1.1.1.1 $
 Last update: $Date: 2002-09-02 09:37:41 $
 ------------

 This file contains the aperiodic server CBS (Total Bandwidth Server)

 Read CBS.h for further details.

**/

/*
 * Copyright (C) 2000 Paolo Gai
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */


#include "cash.h"
#include <ll/stdio.h>
#include <ll/string.h>
#include <kernel/model.h>
#include <kernel/descr.h>
#include <kernel/var.h>
#include <kernel/func.h>

/*+ 4 debug purposes +*/
#undef CBS_TEST

#ifdef TESTG
#include "drivers/glib.h"
TIME x,oldx;
extern TIME starttime;
#endif




     

/*+ Status used in the level +*/
#define CBSGHD_IDLE          APER_STATUS_BASE   /*+ waiting the activation +*/
#define CBSGHD_ZOMBIE        APER_STATUS_BASE+1 /*+ waiting the period end +*/
#define CBSGHD_DELAY         APER_STATUS_BASE+2 /*+ waiting the delay end  +*/

/* structure of an element of the capacity queue  */
struct cap_queue {
  int              cap;
  struct timespec  dead;
  struct cap_queue *next;
};

/*+ the level redefinition for the CBS_HD level +*/
typedef struct {
  level_des l;     /*+ the standard level descriptor          +*/

  /* The wcet are stored in the task descriptor, but we need
     an array for the deadlines. We can't use the timespec_priority
     field because it is used by the master level!!!...
     Notice that however the use of the timespec_priority field
     does not cause any problem...                     */

  struct timespec cbsghd_dline[MAX_PROC]; /*+ CBSGHD deadlines      +*/
 
  TIME period[MAX_PROC]; /*+ CBSGHD activation period            +*/

  TIME maxperiod[MAX_PROC]; /*+ maximum period of each elastic task    +*/
 
  int cremaining[MAX_PROC]; /*+ instance remaining computation time +*/

  TIME act_period[MAX_PROC]; /*+ actual period of each elastic task: it
                               must be less than maxperiod!!!        +*/

  TIME last_response_time[MAX_PROC]; /* response time of the last instance */
 
  TIME cnormal[MAX_PROC]; /*+ CBSGHD normal computation time    +*/

  struct timespec reactivation_time[MAX_PROC];
        /*+ the time at witch  the reactivation timer is post +*/
  int reactivation_timer[MAX_PROC];
                                   /*+ the recativation timer +*/

  struct cap_queue *queue;         /* pointer to the spare capacity queue */

  int flags;       /*+ the init flags...                      +*/

  bandwidth_t U;   /*+ the used bandwidth by the server       +*/

  int idle;         /* the idle flag...  */
 
  struct timespec start_idle; /*gives the start time of the last idle period */
 
  LEVEL scheduling_level;

} CBSGHD_level_des;


/* insert a capacity in the queue capacity ordering by deadline */

static int c_insert(struct timespec dead, int cap, struct cap_queue **que,
                     PID p)
{
  struct cap_queue *prev, *n, *new;

    prev = NULL;
    n = *que;

    while ((n != NULL) &&
           !TIMESPEC_A_LT_B(&dead, &n->dead)) {
        prev = n;
        n = n->next;
    }

   
    new = (struct cap_queue *)kern_alloc(sizeof(struct cap_queue));
    if (new == NULL) {
      kern_printf("\nNew cash_queue element failed\n");
      kern_raise(XUNVALID_TASK, p);
      return -1;
    }
    new->next = NULL;
    new->cap = cap;
    new->dead = dead;
   
    if (prev != NULL)
      prev->next = new;
    else
      *que = new;

    if (n != NULL)
      new->next = n;
    return 0;
}

/* extract the first element from the capacity queue */

static int c_extractfirst(struct cap_queue **que)
{
    struct cap_queue *p = *que;


    if (*que == NULL) return(-1);
   
    *que = (*que)->next;
   
    kern_free(p, sizeof(struct cap_queue));
    return(1);
}

/* read data of the first element from the capacity queue */

static void c_readfirst(struct timespec *d, int *c, struct cap_queue *que)
{
    *d = que->dead;
    *c = que->cap;
}

/* write data of the first element from the capacity queue */

static void c_writefirst(struct timespec dead, int cap, struct cap_queue *que)
{
    que->dead = dead;
    que->cap = cap;
}


static void CBSGHD_activation(CBSGHD_level_des *lev,
                             PID p,
                             struct timespec *acttime)
{
  JOB_TASK_MODEL job;
 
 
  /* This rule is used when we recharge the budget at initial task activation
     and each time a new task instance must be activated  */
 
  if (TIMESPEC_A_GT_B(acttime, &lev->cbsghd_dline[p])) {
    /* we modify the deadline ... */
    TIMESPEC_ASSIGN(&lev->cbsghd_dline[p], acttime);
  }

  lev->act_period[p] = 0;
 
  if (proc_table[p].avail_time > 0)
    proc_table[p].avail_time = 0;




  /* there is a while because if the wcet is << than the system tick
     we need to postpone the deadline many times */
  while (proc_table[p].avail_time <= 0) {
 
    /* A spare capacity is inserted in the capacity queue!! */
    ADDUSEC2TIMESPEC(lev->period[p], &lev->cbsghd_dline[p]);
    lev->act_period[p] += lev->period[p];
    c_insert(lev->cbsghd_dline[p], lev->cnormal[p], &lev->queue, p);
   
   
    /* it exploits available capacities from the capacity queue */
    while (proc_table[p].avail_time < (int)lev->cnormal[p] &&
           lev->queue != NULL) {
      struct timespec dead;
      int             cap, delta;
      delta = lev->cnormal[p] - proc_table[p].avail_time;
      c_readfirst(&dead, &cap, lev->queue);
      if (!TIMESPEC_A_GT_B(&dead, &lev->cbsghd_dline[p])) {
        if (cap > delta) {
          proc_table[p].avail_time += delta;
          c_writefirst(dead, cap - delta, lev->queue);
        }
        else {
          proc_table[p].avail_time += cap;
          c_extractfirst(&lev->queue);
        }
      }
      else
        break;
    }
  }
   
  lev->cremaining[p] = proc_table[p].wcet - proc_table[p].avail_time;
 

#ifdef TESTG
  if (starttime && p == 3) {
    oldx = x;
    x = ((lev->cbsghd_dline[p].tv_sec*1000000+lev->cbsghd_dline[p].tv_nsec/1000)/5000 - starttime) + 20;
    //      kern_printf("(a%d)",lev->cbsghd_dline[p].tv_sec*1000000+lev->cbsghd_dline[p].tv_nsec/1000);
    if (oldx > x) sys_end();
    if (x<640)
      grx_plot(x, 15, 8);
  }
#endif

  /* and, finally, we reinsert the task in the master level */
  job_task_default_model(job, lev->cbsghd_dline[p]);
  job_task_def_yesexc(job);
  level_table[ lev->scheduling_level ]->
    guest_create(lev->scheduling_level, p, (TASK_MODEL *)&job);
  level_table[ lev->scheduling_level ]->
    guest_activate(lev->scheduling_level, p);
}


static char *CBSGHD_status_to_a(WORD status)
{
  if (status < MODULE_STATUS_BASE)
    return status_to_a(status);

  switch (status) {
    case CBSGHD_IDLE   : return "CBSGHD_Idle";
    case CBSGHD_ZOMBIE : return "CBSGHD_Zombie";
    case CBSGHD_DELAY  : return "CBSGHD_Delay";
    default         : return "CBSGHD_Unknown";
  }
}




/* this is the periodic reactivation of the task... */
static void CBSGHD_timer_reactivate(void *par)
{
  PID p = (PID) par;
  CBSGHD_level_des *lev;

  lev = (CBSGHD_level_des *)level_table[proc_table[p].task_level];

  if (proc_table[p].status == CBSGHD_IDLE) {
    /* the task has finished the current activation and must be
       reactivated */
   
    /* request_time represents the time of the last instance release!! */
    TIMESPEC_ASSIGN(&proc_table[p].request_time, &lev->reactivation_time[p]);
 
    /* If idle=1, then we have to discharge the capacities stored in
       the capacity queue up to the length of the idle interval */
    if (lev->idle == 1) {
      TIME interval;
      struct timespec delta;
      lev->idle = 0;
      SUBTIMESPEC(&proc_table[p].request_time, &lev->start_idle, &delta);
      /* length of the idle interval expressed in usec! */
      interval = TIMESPEC2NANOSEC(&delta) / 1000;

      /* it discharge the available capacities from the capacity queue */
      while (interval > 0 && lev->queue != NULL) {
        struct timespec dead;
        int             cap;
        c_readfirst(&dead, &cap, lev->queue);
        if (cap > interval) {
          c_writefirst(dead, cap - interval, lev->queue);
          interval = 0;
        }
        else {
          interval -= cap;
          c_extractfirst(&lev->queue);
        }      
      }
    }

    CBSGHD_activation(lev,p,&lev->reactivation_time[p]);

    /* check the constraint on the maximum period permitted... */
    if (lev->act_period[p] > lev->maxperiod[p]) {
      kern_printf("Deadline miss(timer_react.! process:%d act_period:%lu maxperiod:%lu\n",
                  p, lev->act_period[p], lev->maxperiod[p]);
      kern_raise(XDEADLINE_MISS,p);
    }
   

    /* Set the reactivation timer */
    TIMESPEC_ASSIGN(&lev->reactivation_time[p], &lev->cbsghd_dline[p]);
    lev->reactivation_timer[p] = kern_event_post(&lev->reactivation_time[p],
                                                 CBSGHD_timer_reactivate,
                                                 (void *)p);
    event_need_reschedule();
  }
  else {
    /* this situation cannot occur */
    kern_printf("Trying to reactivate a task which is not IDLE!!!/n");
    kern_raise(XUNVALID_TASK,p);
  }
}





static void CBSGHD_avail_time_check(CBSGHD_level_des *lev, PID p)
{
 
  /*+ if the capacity became negative the remaining computation time
    is diminuished.... +*/
  /* if (p==4)
    kern_printf("(old dead:%d av_time:%d crem:%d)\n",
                lev->cbsghd_dline[p].tv_sec*1000000+
                lev->cbsghd_dline[p].tv_nsec/1000, proc_table[p].avail_time,
                lev->cremaining[p]);  */

 
  if (proc_table[p].avail_time < 0)
    lev->cremaining[p] += proc_table[p].avail_time;
     
  if (lev->cremaining[p] <= 0) {
    kern_printf("Task:%d   WCET violation \n", p);
    kern_raise(XWCET_VIOLATION, p);
    ll_abort(666);
  }

 
  /* there is a while because if the wcet is << than the system tick
     we need to postpone the deadline many times */
  while (proc_table[p].avail_time <= 0) {
    /* it exploits available capacities from the capacity queue */
    while (proc_table[p].avail_time < lev->cremaining[p]
           && lev->queue != NULL) {
      struct timespec dead;
      int             cap, delta;
      delta = lev->cremaining[p] - proc_table[p].avail_time;
      c_readfirst(&dead, &cap, lev->queue);
      if (!TIMESPEC_A_GT_B(&dead, &lev->cbsghd_dline[p])) {
        if (cap > delta) {
          proc_table[p].avail_time += delta;
          c_writefirst(dead, cap - delta, lev->queue);
        }
        else {
          proc_table[p].avail_time += cap;
          c_extractfirst(&lev->queue);
        }
      }
      else
        break;
    }

    /* if (p==5 && proc_table[p].avail_time <= 0 &&
       lev->cremaining[p] > lev->cnormal[p])
       kern_printf("(inter dead:%d av_time:%d crem:%d)\n",
       lev->cbsghd_dline[p].tv_sec*1000000+
       lev->cbsghd_dline[p].tv_nsec/1000, proc_table[p].avail_time,
       lev->cremaining[p]); */
   
   
    /* The remaining computation time is modified according
       to the new budget! */
    if (proc_table[p].avail_time > 0)
      lev->cremaining[p] -= proc_table[p].avail_time;
    else {
      /* the CBSGHD rule for recharging the capacity:  */
      if (lev->cremaining[p] > lev->cnormal[p]) {
        ADDUSEC2TIMESPEC(lev->period[p], &lev->cbsghd_dline[p]);
        lev->act_period[p] += lev->period[p];
        /* A spare capacity is inserted in the capacity queue!! */
        c_insert(lev->cbsghd_dline[p], lev->cnormal[p], &lev->queue, p);
      }
      else {
        TIME t;
        t = (lev->cremaining[p] * lev->period[p]) / lev->cnormal[p];
        ADDUSEC2TIMESPEC(t, &lev->cbsghd_dline[p]);
        lev->act_period[p] += t;
        /* A spare capacity is inserted in the capacity queue!! */
        c_insert(lev->cbsghd_dline[p], lev->cremaining[p], &lev->queue, p);
      }
    }
  }
 
  /*  if (p==4)
    kern_printf("n dead:%d av_time:%d crem:%d)\n",
                lev->cbsghd_dline[p].tv_sec*1000000+
                lev->cbsghd_dline[p].tv_nsec/1000, proc_table[p].avail_time,
                lev->cremaining[p]);  */

  /* check the constraint on the maximum period permitted... */
  if (lev->act_period[p] > lev->maxperiod[p]) {
    /*kern_printf("n dead:%d av_time:%d crem:%d)\n",
                lev->cbsghd_dline[p].tv_sec*1000000+
                lev->cbsghd_dline[p].tv_nsec/1000, proc_table[p].avail_time,
                lev->cremaining[p]);  */
    kern_printf("Deadline miss(av.time_check! process:%d act_period:%lu maxperiod:%lu\n",
                p, lev->act_period[p], lev->maxperiod[p]);
    kern_raise(XDEADLINE_MISS,p);
  }


 
  if (TIMESPEC_A_LT_B(&lev->reactivation_time[p], &lev->cbsghd_dline[p])) {
    /* we delete the reactivation timer */
    event_delete(lev->reactivation_timer[p]);
    /* repost the event at the next instance deadline... */
    lev->reactivation_time[p] = lev->cbsghd_dline[p];
    lev->reactivation_timer[p] = kern_event_post(&lev->reactivation_time[p],
                                                 CBSGHD_timer_reactivate,
                                                 (void *)p);
  }
 
#ifdef TESTG
  if (starttime && p == 3) {
    oldx = x;
    x = ((lev->cbsghd_dline[p].tv_sec*1000000+
          lev->cbsghd_dline[p].tv_nsec/1000)/5000 - starttime) + 20;
    //      kern_printf("(e%d avail%d)",lev->cbsghd_dline[p].tv_sec*1000000+
                        lev->cbsghd_dline[p].tv_nsec/1000,proc_table[p].avail_time);
    if (oldx > x) sys_end();
    if (x<640)
      grx_plot(x, 15, 2);
  }
#endif
 
}


/*+ this function is called when a killed or ended task reach the
  period end +*/
static void CBSGHD_timer_zombie(void *par)
{
  PID p = (PID) par;
  CBSGHD_level_des *lev;

  lev = (CBSGHD_level_des *)level_table[proc_table[p].task_level];

  /* we finally put the task in the FREE status */
  proc_table[p].status = FREE;
  q_insertfirst(p,&freedesc);

  /* and free the allocated bandwidth */
  lev->U -= (MAX_BANDWIDTH/lev->period[p]) * lev->cnormal[p];

}


static int CBSGHD_level_accept_task_model(LEVEL l, TASK_MODEL *m)
{
 

  if (m->pclass == ELASTIC_HARD_PCLASS || m->pclass ==
      (ELASTIC_HARD_PCLASS | l)) {
    ELASTIC_HARD_TASK_MODEL *s = (ELASTIC_HARD_TASK_MODEL *)m;
    bandwidth_t b1, b2;
    /*  kern_printf("accept :ELASTIC TASK found!!!!!!\n"); */
    b1 = (MAX_BANDWIDTH / s->period) * s->cnormal;
    b2 = (MAX_BANDWIDTH / s->maxperiod) * s->wcet;
    if (s->wcet && s->cnormal && s->period && s->maxperiod &&
        s->wcet >= s->cnormal && b1 >= b2)
      return 0;
    /*  kern_printf("period: %d maxperiod: %d cnormal: %d wcet: %d, b1: %d b2:
              %d\n", s->period, s->maxperiod, s->cnormal, s->wcet, b1, b2); */
  }
  return -1;
}

static int CBSGHD_level_accept_guest_model(LEVEL l, TASK_MODEL *m)
{
  return -1;
}

static char *onoff(int i)
{
  if (i)
    return "On ";
  else
    return "Off";
}

static void CBSGHD_level_status(LEVEL l)
{
  CBSGHD_level_des *lev = (CBSGHD_level_des *)(level_table[l]);
  PID p;

  kern_printf("On-line guarantee : %s\n",
              onoff(lev->flags & CBSGHD_ENABLE_GUARANTEE));
  kern_printf("Used Bandwidth    : %u/%u\n",
              lev->U, MAX_BANDWIDTH);

  for (p=0; p<MAX_PROC; p++)
    if (proc_table[p].task_level == l && proc_table[p].status != FREE )
      kern_printf("Pid: %2d Name: %10s Period: %9ld Dline: %9ld.%6ld Stat: %s\n",
                  p,
                  proc_table[p].name,
                  lev->period[p],
                  lev->cbsghd_dline[p].tv_sec,
                  lev->cbsghd_dline[p].tv_nsec/1000,
                  CBSGHD_status_to_a(proc_table[p].status));
}

static PID CBSGHD_level_scheduler(LEVEL l)
{
  CBSGHD_level_des *lev = (CBSGHD_level_des *)(level_table[l]);
 
  /* it stores the actual time and set the IDLE flag in order to handle
     the capacity queue discharging!!! */
  lev->idle = 1;
  ll_gettime(TIME_EXACT, &lev->start_idle);

 
  /* the CBSGHD don't schedule anything...
     it's an EDF level or similar that do it! */
  return NIL;
}

/* The on-line guarantee is enabled only if the appropriate flag is set... */
static int CBSGHD_level_guarantee(LEVEL l, bandwidth_t *freebandwidth)
{
  CBSGHD_level_des *lev = (CBSGHD_level_des *)(level_table[l]);

  if (lev->flags & CBSGHD_FAILED_GUARANTEE) {
    *freebandwidth = 0;
    //kern_printf("guarantee :garanzia fallita!!!!!!\n");
    return 0;
  }
  else if (*freebandwidth >= lev->U) {
    *freebandwidth -= lev->U;
    return 1;
  }
  else {
    //kern_printf("guarantee :garanzia fallita per mancanza di banda!!!!!!\n");
    //kern_printf("freeband: %d request band: %d", *freebandwidth, lev->U);
    return 0;
  }
}

static int CBSGHD_task_create(LEVEL l, PID p, TASK_MODEL *m)
{
  CBSGHD_level_des *lev = (CBSGHD_level_des *)(level_table[l]);

  /* if the CBSGHD_task_create is called, then the pclass must be a
     valid pclass. */
  ELASTIC_HARD_TASK_MODEL *s = (ELASTIC_HARD_TASK_MODEL *)m;

  /* Enable wcet check */
  proc_table[p].avail_time = 0;
  proc_table[p].wcet       = s->wcet;
  proc_table[p].control   |= CONTROL_CAP;

  lev->period[p] = s->period;
  lev->maxperiod[p] = s->maxperiod;
  lev->cnormal[p] = s->cnormal;
  NULL_TIMESPEC(&lev->cbsghd_dline[p]);
 

  /* update the bandwidth... */
  if (lev->flags & CBSGHD_ENABLE_GUARANTEE) {
    bandwidth_t b;
    b = (MAX_BANDWIDTH / s->period) * s->cnormal;

    /* really update lev->U, checking an overflow... */
    if (MAX_BANDWIDTH - lev->U > b)
      lev->U += b;
    else
      /* The task can NOT be guaranteed (U>MAX_BANDWIDTH)...
         (see EDF.c) */
      lev->flags |= CBSGHD_FAILED_GUARANTEE;
  }

 

  return 0; /* OK, also if the task cannot be guaranteed... */
}

static void CBSGHD_task_detach(LEVEL l, PID p)
{
  /* the CBSGHD level doesn't introduce any dinamic allocated new field.
     we have only to reset the NO_GUARANTEE FIELD and decrement the allocated
     bandwidth */

  CBSGHD_level_des *lev = (CBSGHD_level_des *)(level_table[l]);

  if (lev->flags & CBSGHD_FAILED_GUARANTEE)
    lev->flags &= ~CBSGHD_FAILED_GUARANTEE;
  else
    lev->U -= (MAX_BANDWIDTH / lev->period[p]) * lev->cnormal[p];

 
}

static int CBSGHD_task_eligible(LEVEL l, PID p)
{
  return 0; /* if the task p is chosen, it is always eligible */
}

#ifdef __TEST1__
  extern int testactive;
  extern struct timespec s_stime[];
  extern TIME s_curr[];
  extern TIME s_PID[];
  extern int useds;
#endif

static void CBSGHD_task_dispatch(LEVEL l, PID p, int nostop)
{
  CBSGHD_level_des *lev = (CBSGHD_level_des *)(level_table[l]);
  level_table[ lev->scheduling_level ]->
    guest_dispatch(lev->scheduling_level,p,nostop);

#ifdef __TEST1__
  if (testactive)
    {
      TIMESPEC_ASSIGN(&s_stime[useds], &schedule_time);
      s_curr[useds] = proc_table[p].avail_time;
      s_PID[useds]  = p;
      useds++;
    }
#endif
}

static void CBSGHD_task_epilogue(LEVEL l, PID p)
{
  CBSGHD_level_des *lev = (CBSGHD_level_des *)(level_table[l]);
  JOB_TASK_MODEL job;

  /* check if the budget is finished... */
  if ( proc_table[p].avail_time <= 0) {
    /* we kill the current activation */
    level_table[ lev->scheduling_level ]->
      guest_end(lev->scheduling_level, p);

    /* we modify the deadline */
    CBSGHD_avail_time_check(lev, p);

    /* and, finally, we reinsert the task in the master level */
    job_task_default_model(job, lev->cbsghd_dline[p]);
    job_task_def_yesexc(job);
    level_table[ lev->scheduling_level ]->
      guest_create(lev->scheduling_level, p, (TASK_MODEL *)&job);
    level_table[ lev->scheduling_level ]->
      guest_activate(lev->scheduling_level, p);
    //    kern_printf("epil : dl %d per %d p %d |\n",
                      //              lev->cbsghd_dline[p].tv_nsec/1000,lev->period[p],p);

  }
  else
    /* the task has been preempted. it returns into the ready queue by
       calling the guest_epilogue... */
    level_table[ lev->scheduling_level ]->
      guest_epilogue(lev->scheduling_level,p);
}

static void CBSGHD_task_activate(LEVEL l, PID p)
{
  CBSGHD_level_des *lev = (CBSGHD_level_des *)(level_table[l]);

  ll_gettime(TIME_EXACT, &proc_table[p].request_time);
 
  /* If idle=1, then we have to discharge the capacities stored in
     the capacity queue up to the length of the idle interval */
  if (lev->idle == 1) {
    TIME interval;
    struct timespec delta;
    lev->idle = 0;
    SUBTIMESPEC(&proc_table[p].request_time, &lev->start_idle, &delta);
    /* length of the idle interval expressed in usec! */
    interval = TIMESPEC2NANOSEC(&delta) / 1000;

    /* it discharge the available capacities from the capacity queue */
    while (interval > 0 && lev->queue != NULL) {
      struct timespec dead;
      int             cap;
      c_readfirst(&dead, &cap, lev->queue);
      if (cap > interval) {
        c_writefirst(dead, cap - interval, lev->queue);
        interval = 0;
      }
      else {
        interval -= cap;
        c_extractfirst(&lev->queue);
      }
    }
  }
 
  CBSGHD_activation(lev, p, &proc_table[p].request_time);


  /* check the constraint on the maximum period permitted... */
  if (lev->act_period[p] > lev->maxperiod[p]) {
      kern_printf("Deadline miss(task_activ.! process:%d act_period:%lu maxperiod:%lu\n",
                  p, lev->act_period[p], lev->maxperiod[p]);
    kern_raise(XDEADLINE_MISS,p);
  }
 
  /* Set the reactivation timer */
  TIMESPEC_ASSIGN(&lev->reactivation_time[p], &lev->cbsghd_dline[p]);
  lev->reactivation_timer[p] = kern_event_post(&lev->reactivation_time[p],
                                                   CBSGHD_timer_reactivate,
                                                   (void *)p);
 
  //  kern_printf("act : %d %d |",lev->cbsghd_dline[p].tv_nsec/1000,p);
}

static void CBSGHD_task_insert(LEVEL l, PID p)
{
  printk("CBSGHD_task_insert\n");
  kern_raise(XUNVALID_TASK,p);
}

static void CBSGHD_task_extract(LEVEL l, PID p)
{
  printk("CBSGHD_task_extract\n");
  kern_raise(XUNVALID_TASK,p);
}

static void CBSGHD_task_endcycle(LEVEL l, PID p)
{
  CBSGHD_level_des *lev = (CBSGHD_level_des *)(level_table[l]);
  struct timespec act_time, res;

  /* It computes the response time of the current instance... */
  ll_gettime(TIME_EXACT, &act_time);
  SUBTIMESPEC(&act_time, &proc_table[p].request_time, &res);
  /* response time expressed in usec! */
  lev->last_response_time[p] = TIMESPEC2NANOSEC(&res) / 1000;
 
  level_table[ lev->scheduling_level ]->
    guest_end(lev->scheduling_level,p);

 
  /* A spare capacity is inserted in the capacity queue!! */
  if (proc_table[p].avail_time > 0) {
    c_insert(lev->cbsghd_dline[p], proc_table[p].avail_time, &lev->queue, p);
    proc_table[p].avail_time = 0;
  }  

 
  proc_table[p].status = CBSGHD_IDLE;
}

static void CBSGHD_task_end(LEVEL l, PID p)
{
  CBSGHD_level_des *lev = (CBSGHD_level_des *)(level_table[l]);

  /* check if the capacity became negative... */
  /* there is a while because if the wcet is << than the system tick
     we need to postpone the deadline many times */
  while (proc_table[p].avail_time < 0) {
    /* the CBSGHD rule for recharging the capacity */
    proc_table[p].avail_time += lev->cnormal[p];
    ADDUSEC2TIMESPEC(lev->period[p], &lev->cbsghd_dline[p]);
  }
 
  level_table[ lev->scheduling_level ]->
    guest_end(lev->scheduling_level,p);

  /* we delete the reactivation timer */
  event_delete(lev->reactivation_timer[p]);
  lev->reactivation_timer[p] = -1;
 

  /* Finally, we post the zombie event. when the end period is reached,
     the task descriptor and banwidth are freed */
  proc_table[p].status = CBSGHD_ZOMBIE;
  lev->reactivation_timer[p] = kern_event_post(&lev->cbsghd_dline[p],
                                               CBSGHD_timer_zombie,
                                               (void *)p);
}

static void CBSGHD_task_sleep(LEVEL l, PID p)
{
  printk("CBSGHD_task_sleep\n");
  kern_raise(XUNVALID_TASK,p);
}

static void CBSGHD_task_delay(LEVEL l, PID p, TIME usdelay)
{
  printk("CBSGHD_task_delay\n");
  kern_raise(XUNVALID_TASK,p);
}


static int CBSGHD_guest_create(LEVEL l, PID p, TASK_MODEL *m)
{ kern_raise(XUNVALID_GUEST,exec_shadow); return 0; }

static void CBSGHD_guest_detach(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void CBSGHD_guest_dispatch(LEVEL l, PID p, int nostop)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void CBSGHD_guest_epilogue(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void CBSGHD_guest_activate(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void CBSGHD_guest_insert(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void CBSGHD_guest_extract(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void CBSGHD_guest_endcycle(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void CBSGHD_guest_end(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void CBSGHD_guest_sleep(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void CBSGHD_guest_delay(LEVEL l, PID p,DWORD tickdelay)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }




/* Registration functions */

/*+ Registration function:
    int flags                 the init flags ... see CBS.h +*/
void CBSGHD_register_level(int flags, LEVEL master)
{
  LEVEL l;            /* the level that we register */
  CBSGHD_level_des *lev;  /* for readableness only */
  PID i;              /* a counter */

  printk("CBSGHD_register_level\n");

  /* request an entry in the level_table */
  l = level_alloc_descriptor();

  printk("    alloco descrittore %d %d\n",l,sizeof(CBSGHD_level_des));

  /* alloc the space needed for the CBSGHD_level_des */
  lev = (CBSGHD_level_des *)kern_alloc(sizeof(CBSGHD_level_des));

  printk("    lev=%d\n",(int)lev);

  /* update the level_table with the new entry */
  level_table[l] = (level_des *)lev;

  /* fill the standard descriptor */
  strncpy(lev->l.level_name,  CBSGHD_LEVELNAME, MAX_LEVELNAME);
  lev->l.level_code               = CBSGHD_LEVEL_CODE;
  lev->l.level_version            = CBSGHD_LEVEL_VERSION;

  lev->l.level_accept_task_model  = CBSGHD_level_accept_task_model;
  lev->l.level_accept_guest_model = CBSGHD_level_accept_guest_model;
  lev->l.level_status             = CBSGHD_level_status;
  lev->l.level_scheduler          = CBSGHD_level_scheduler;

  if (flags & CBSGHD_ENABLE_GUARANTEE)
    lev->l.level_guarantee        = CBSGHD_level_guarantee;
  else
    lev->l.level_guarantee        = NULL;

  lev->l.task_create              = CBSGHD_task_create;
  lev->l.task_detach              = CBSGHD_task_detach;
  lev->l.task_eligible            = CBSGHD_task_eligible;
  lev->l.task_dispatch            = CBSGHD_task_dispatch;
  lev->l.task_epilogue            = CBSGHD_task_epilogue;
  lev->l.task_activate            = CBSGHD_task_activate;
  lev->l.task_insert              = CBSGHD_task_insert;
  lev->l.task_extract             = CBSGHD_task_extract;
  lev->l.task_endcycle            = CBSGHD_task_endcycle;
  lev->l.task_end                 = CBSGHD_task_end;
  lev->l.task_sleep               = CBSGHD_task_sleep;
  lev->l.task_delay               = CBSGHD_task_delay;

  lev->l.guest_create             = CBSGHD_guest_create;
  lev->l.guest_detach             = CBSGHD_guest_detach;
  lev->l.guest_dispatch           = CBSGHD_guest_dispatch;
  lev->l.guest_epilogue           = CBSGHD_guest_epilogue;
  lev->l.guest_activate           = CBSGHD_guest_activate;
  lev->l.guest_insert             = CBSGHD_guest_insert;
  lev->l.guest_extract            = CBSGHD_guest_extract;
  lev->l.guest_endcycle           = CBSGHD_guest_endcycle;
  lev->l.guest_end                = CBSGHD_guest_end;
  lev->l.guest_sleep              = CBSGHD_guest_sleep;
  lev->l.guest_delay              = CBSGHD_guest_delay;

  /* fill the CBSGHD descriptor part */
  for (i=0; i<MAX_PROC; i++) {
     NULL_TIMESPEC(&lev->cbsghd_dline[i]);
     lev->period[i] = 0;
     lev->last_response_time[i] = 0;
     NULL_TIMESPEC(&lev->reactivation_time[i]);
     lev->reactivation_timer[i] = -1;
  }


  lev->U = 0;
  lev->idle = 0;
  lev->queue = NULL;
 
  lev->scheduling_level = master;

  lev->flags = flags & 0x07;
}


int CBSGHD_get_response_time(LEVEL l, PID p)
{
  CBSGHD_level_des *lev = (CBSGHD_level_des *)(level_table[l]);
  return lev->last_response_time[p];
}


bandwidth_t CBSGHD_usedbandwidth(LEVEL l)
{
  CBSGHD_level_des *lev = (CBSGHD_level_des *)(level_table[l]);
  if (lev->l.level_code    == CBSGHD_LEVEL_CODE &&
      lev->l.level_version == CBSGHD_LEVEL_VERSION)
    return lev->U;
  else
    return 0;
}